1) Field of the Invention
This invention relates to game pieces, specifically to printed game pieces which reveal concealed information when exposed to an additive light source.
2) Description of the Related Art
In numerous types of situations and environments it is desirable or necessary to provide a substrate which carries a hidden image. That hidden image might be a word, number, icon, logo, drawing, picture, depiction, marking, message, pattern, or some other indicia. For example, when a sheet with a hidden image is used as a game piece, its hidden image, once revealed, may be used to:
(a) communicate the name of a particular prize in a sweepstakes; PA1 (b) communicate a particular number which has to be matched identically to a predetermined "winning" number in order to win a prize; PA1 (c) communicate a particular word which has to be matched identically to a predetermined "winning" word in order to win a prize; or PA1 (d) communicate a particular image, picture, logo, or icon in order to win a prize. PA1 (a) to provide an additive-light activated hidden image game piece which will reveal its hidden image when exposed to relatively low levels of additive light, such as those typically emanated by a computer monitor; PA1 (b) to provide a method of producing an additive-light activated hidden image game piece which will reveal its hidden image when exposed to relatively low levels of additive light, such as those typically emanated by a computer monitor; and PA1 (c) to provide a method of producing an additive-light activated hidden image game piece which creates high quality products.
Often, there is a predetermined "seeding" structure inherent in a game-piece-delivered sweepstakes in which only a certain predetermined number of "winning" game pieces are printed and distributed for each corresponding prize level. However, because the game piece's potentially "winning" information is hidden, no contest participant has a chance to win unless he or she interacts with a game piece to reveal its concealed image.
There are numerous ways to create a substrate which carries a hidden image; all of these techniques could theoretically be used to create a game piece with a hidden image. For example, in some merchandising schemes a hidden image is present on a substrate and can be read only after a coating is removed by scratch removal of the coating or other removal of the coating. Some types of hidden images on a substrate appear only after a chemical solution is applied to the substrate. Some types of hidden images which are carried by a substrate appear only after a reaction occurs in the image when the substrate is subjected to artificial or natural light. Some types of hidden images which are carried by a substrate are made to appear only after the substrate is subjected to a significant temperature change. Some types of hidden images which are carried by a substrate are made visible only when observed in special kind of light rays. Some types of hidden images which are carried upon a substrate are made visible for reading only when viewed through special optics. Several other methods for applying and for reading hidden images have been created.
Devices have been created in which a hidden image carried upon a substrate will only become visible when exposed to specific color(s) of light in the visible spectrum. Typically, such devices are created by using printing, or some other technique, to apply images to the substrate. For example, the image which is to be hidden may be applied to the substrate using one color. Then the marking, pattern, or image which has been designed to conceal the hidden image may be applied to the same portion of the substrate as the hidden image, using a different color. Generally, the concealing marking, pattern, or image is designed to cover, surround, or otherwise camouflage the concealed image in a way that makes the concealed image imperceptible in normal light. Often, a "mezzotint" pattern is used for the concealing marking, pattern, or image ("mezzotint" refers to a computer-generated pattern which has red and yellow elements; such a pattern is often used to disguise an image printed in light blue). An image which has been hidden in this manner may be revealed by exposing the substrate to light of a color similar to the concealing marking, pattern, or image.
However, all of the presently known methods for creating a light-activated hidden image game piece have proved unsuitable for creating a hidden image game piece which is capable of being activated by the low-intensity light emanated by a typical computer monitor screen. In the past, light-activated hidden image game pieces have typically: 1) employed a paper substrate; 2) not required that the density of the inks applied to the substrate be limited to a specific range; and 3) used a coloring filtering device to provide the specific color of light required to activate the game piece.
A number of game pieces have been created in which a previously hidden image will be revealed when the game piece is viewed through a color filtering device. A color filtering device tends to prevent the transmission of light rays of a substantially different color than the filtering device. For example, if the primary color red is used for the filter, it will absorb light of the other primary colors blue and green. Accordingly, objects which are otherwise blue or green will appear black (in the absence of light transmission); red objects will remain red; white objects will also be seen as red, as the blue and green components of the white light are absorbed by the filter. Accordingly, on a white background, an image in blue may be surrounded and camouflaged by red markings so as to appear substantially illegible when viewed with the naked eye. When viewed through a red filter, however, the image can be seen as a black image on a solid red background. U.S. Pat. No. 5,312,656 to Michaels (1994) shows the use of red filter (specifically, a transparent red plate in a toy picnic set) to reveal a hidden image in this way. A similar use of a red filter to reveal a hidden image is described in U.S. Pat. No. 5,401,032 to Barnhart and Smith (1995).
However, an approach other than the color-filtering technique is required when designing a hidden-image game piece capable of being activated by a device such as a computer monitor. A color filter uses ambient natural or artificial light, and screens out those colors of light which are undesired. But it is also possible to "add" light of a specific color to a game piece, without filtering the ambient light. In the case of a computer monitor, the "additive" light needed for activation of the game piece may be obtained by placing the game piece on a specifically-colored area of the screen of an operating monitor. This action floods the game piece with the specific type of colored light required for activation, and reveals the hidden image.
By way of example, it would be possible to make a paper game piece which was designed to be activated by red light when placed upon a television screen. In such a game piece, a printed red and yellow mezzotint pattern could be used to conceal a hidden image printed in light blue. When such a game piece was flooded with the additive red light supplied by a red square projected on the television screen from the source of transmission, the game piece's hidden message would be seen as a black image on a red background.
However, a paper game piece designed to be activated by a relatively high-intensity light source, such as a television, cannot be used with a relatively low-intensity light source, such as a computer monitor. The intensity of the additive light provided by a computer monitor is generally only 80-120 candlepower (the intensity a source of light is measured in standard units known as "candlepower;" one candlepower is equal to the light emitted by one standardized candle). A computer monitor's low-intensity light cannot activate a hidden-image paper game piece because it cannot overcome the papers opacity to reveal the hidden image. Therefore, a traditional paper substrate cannot be used to create an additive-light game piece designed to be activated by a computer monitor.
In the past, the density of the ink application used in printing an additive-light activated hidden image game piece has been of relatively minor importance. However, when producing an additive-light activated hidden image game piece which is designed for use with computer monitors, or other devices which emanate relatively low levels of additive light, the density of the ink application must be controlled within a narrow range. If the density is too high, it will serve to block the additive light needed to reveal the hidden image. If the density is too low, the hidden image and/or the concealing image will be illegible.
In the printing industry, "density" is a term of art. It refers to the thickness of a coating (typically, ink) which is applied to a substrate. One unit of density equals 1/100,000 (one one-hundred thousandth) of an inch of coating thickness. Therefore, density of 100 equals 1/1000 (one one-thousandth) of an inch of coating thickness, or one mil. Printers typically use a tool known as a "densitometer" to measure coating thickness.
The phrase "dull coating" is also a term of art in the printing industry. It is often used interchangeably with the terms "dull varnish" and "frost coating." It refers to a coating which is traditionally used by printers to enhance the appearance and durability of printed matter. Such a coating may be oil-based or water-based. A water-based dull coating is commonly referred to as an "aqueous" coating.